The antelope is a Class-A protected animal and is uniquely found on the Tibetan Plateau. In the past there were more than a million antelopes in the area, but the population has been decimated by illegal poaching because of the value of their fur. By the 1990s, their numbers had fallen to less than 70,000, a population reduction of over 90%. Recently, with increased protection efforts, the antelope population is slowly recovering. Male antelopes have long straight horns and female antelopes are hornless. Every year, the female antelopes form a large herd and make a lengthy journey to the northern uninhabited part of the Plateau to give birth. It is only recently that their migration route was verified by scientists. The special animal passageways incorporated in the construction of the Qinghai-Tibet Railway were designed specifically for migrating animals like the antelope.